Generalized non-reciprocity in an optomechanical circuit via synthetic magnetism and reservoir engineering

• Published in: Nature physics Vol. 13; no. 5; pp. 465 - 471
• Main Authors: Fang, Kejie, Luo, Jie, Metelmann, Anja, Matheny, Matthew H., Marquardt, Florian, Clerk, Aashish A., Painter, Oskar
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.05.2017; Nature Publishing Group
• Subjects: 639/766/1130/2800; 639/766/400; Atomic; Circuit design; Circuits; Classical and Continuum Physics; Complex Systems; Condensed Matter Physics; Coupling; Devices; Holes; Lasers; Magnetism; Mathematical and Computational Physics; Molecular; Optical and Plasma Physics; Optoelectronics; Phonons; Photons; Physics; Reservoir engineering; Silicon; Theoretical
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/nphys4009

Synthetic magnetism has been used to control charge neutral excitations for applications ranging from classical beam steering to quantum simulation. In optomechanics, radiation-pressure-induced parametric coupling between optical (photon) and mechanical (phonon) excitations may be used to break time-reversal symmetry, providing the prerequisite for synthetic magnetism. Here we design and fabricate a silicon optomechanical circuit with both optical and mechanical connectivity between two optomechanical cavities. Driving the two cavities with phase-correlated laser light results in a synthetic magnetic flux, which, in combination with dissipative coupling to the mechanical bath, leads to non-reciprocal transport of photons with 35 dB of isolation. Additionally, optical pumping with blue-detuned light manifests as a particle non-conserving interaction between photons and phonons, resulting in directional optical amplification of 12 dB in the isolator through-direction. These results suggest the possibility of using optomechanical circuits to create a more general class of non-reciprocal optical devices, and further, to enable new topological phases for both light and sound on a microchip. Combining synthetic magnetism and controlled dissipation, researchers created an optomechanical device in which photons and phonons are coupled, enabling non-reciprocal (asymmetric) photon transport and directional amplification.